1. Field of the Invention
The present invention relates generally to a disk drive, and more particularly to a magneto-optical disk drive having an optical head and a magnetic head.
2. Description of the Related Art
Increasing recording density in a magneto-optical disk drive has been progressively required as various systems for information recording have been developed. According to an optical modulation system adopted by the ISO standard, a laser beam is modulated with recording data while an external magnetic field is applied in a fixed direction, thereby recording information on a magneto-optical recording medium. In this optical modulation system, information recording density is limited by the size of a beam spot on the magneto-optical recording medium.
In contrast therewith, according to a magnetic field modulation system, an external magnetic field is modulated with recording data while a laser beam having a fixed intensity is directed onto a magneto-optical recording medium. In this magnetic field modulation system, beam spots can be overlapped on the magneto-optical recording medium. This system is considered to be more advantageous for high-density recording than the optical modulation system. Since the external magnetic field is modulated with the recording data at a high speed in the magnetic field modulation system, a flying magnetic head is used as a magnetic head in this system. The flying magnetic head used in this system is substantially the same in shape and operation principle as that used in a magnetic disk drive. When a magneto-optical disk as the magneto-optical recording medium is rotated, the magnetic head flies from the surface of the disk at a height of about 10 xcexcm to record data in a beam spot.
In using a magneto-optical disk drive, it is essential to exchange disks. Accordingly, the magneto-optical disk drive is required to have a mechanism for loading and unloading a disk, wherein when ejecting the disk from the disk drive, a magnetic head is lifted about several millimeters from the disk, that is, unloaded for the purpose of preventing damage to the magnetic head. When inserting the disk into the disk drive, the magnetic head is lowered to the disk, that is, loaded. In a conventional mechanism as described in Japanese Patent Laid-open No. 6-215435, a member for lifting a suspension on which a magnetic head is mounted is retracted from a lift position in concert with an operation of inserting/ejecting a disk into/from a disk drive.
Such conventional mechanisms will now be described with reference to FIGS. 1A and 1B. In the conventional mechanism shown in FIG. 1A, a magnetic head assembly 2 includes a suspension 4 and a magnetic head 6 mounted on a front end portion of the suspension 4. Reference numeral 8 denotes a suspension lifting member. The suspension lifting member 8 is moved from a lift position shown in the direction of an arrow A, that is, in a direction perpendicular to the longitudinal direction of the suspension 4, thereby allowing contact of the magnetic head 6 with a disk (not shown) by a spring force of the suspension 4.
In the conventional mechanism shown in FIG. 1B, a suspension lifting member 10 is moved in the direction of an arrow B, that is, in a direction perpendicular to a disk 12, thereby allowing contact of the magnetic head 6 with the disk 12 by a spring force of the suspension 4. In such a conventional magneto-optical disk drive, the suspension lifting member 8 or 10 is moved or released in the direction A shown in FIG. 1A or in the direction B shown in FIG. 1B in making contact of the magnetic head 6 and the disk. Accordingly, at the moment the suspension lifting member 8 or 10 is released, the suspension 4 is returned by its own spring force toward the disk surface, causing a possibility of striking of the magnetic head 6 against the disk surface to damage the disk or the magnetic head.
In another aspect, the magnetic field modulation type magneto-optical disk drive adopts a contact start and stop (CSS) system wherein a disk starts rotating after a magnetic head comes into contact with the disk. Accordingly, a spindle motor for rotating the disk is required to exert a starting torque overcoming a static frictional force between the magnetic head and the disk, hindering attempts to reduce the size of the motor. Further, in the disk drive disclosed in Japanese Patent Laid-open No. 6-215435, a solenoid is energized only during ejection of a disk cartridge from the disk drive to lift the magnetic head from the disk. However, after the eject operation of the disk cartridge is ended, the magnetic head is returned to its original position, so that it is necessary to provide means for detecting an operation of subsequently inserted or loading disk cartridge into the disk drive and for lifting the magnetic head again. Thus, the configuration of the disk drive is complicated.
It is therefore an object of the present invention to provide a disk drive having a simple mechanism for loading and unloading a magnetic head with respect to a disk without damaging the disk and the magnetic head.
It is another object of the present invention to provide a disk drive which can reduce a static frictional force between a magnetic head and a disk to thereby reduce a load to a spindle motor.
It is a further object of the present invention to provide a disk drive having a mechanism for keeping a magnetic head lifted after ejecting a disk cartridge from the disk drive.
In accordance with an aspect of the present invention, there is provided a disk drive adapted to accept and eject a disk cartridge accommodating a disk, comprising a drive base; a carriage mounted on said drive base so as to be movable in a radial direction of said disk; driving means for moving said carriage; a magnetic head assembly mounted on said carriage and having a magnetic head; cartridge ejecting means having an eject arm pivotally moving in a first direction when said disk cartridge is inserted into said disk drive, while pivotally moving in a second direction opposite to said first direction when said disk cartridge is ejected from said disk drive; and a magnetic head lifter pivotally movable between a first position where said magnetic head lifter is engaged with said magnetic head assembly to lift said magnetic head and a second position where said magnetic head lifter is pushed by an insertion force of said disk cartridge inserted into said disk drive to allow contact of said magnetic head with said disk.
Preferably, the magnetic head assembly includes a suspension and the magnetic head supported at a front end portion of the suspension. The magnetic head lifter selectively engages the suspension to lift the magnetic head at the first position. Preferably, the magnetic head lifter is pivotally movable by a coil spring. More preferably, the magnetic head lifter is integrally formed with the coil spring. Preferably, the selective lifting of the magnetic head by the magnetic head lifter is performed at an outermost or innermost circumferential portion of the disk.
In accordance with another aspect of the present invention, there is provided a disk drive adapted to accept and eject a disk cartridge accommodating a disk, comprising a drive base; a carriage mounted on said drive base so as to be movable in a radial direction of said disk; driving means for moving said carriage; a magnetic head assembly mounted on said carriage and having a magnetic head; a magnetic head lifter movable between a first position where said magnetic head lifter is engaged with said magnetic head assembly to lift said magnetic head and a second position where said magnetic head lifter is disengaged from said magnetic head assembly; biasing means for moving said magnetic head lifter to said first position; and a solenoid for moving said magnetic head lifter to said second position against a biasing force of said biasing means.
In accordance with a further aspect of the present invention, there is provided a disk drive adapted to accept and eject a disk cartridge accommodating a disk, comprising a drive base; a carriage mounted on said drive base so as to be movable in a radial direction of said disk; driving means for moving said carriage; a head arm fixed to said carriage; a suspension fixed at its base end portion to said head arm; a magnetic head mounted on a front end portion of said suspension; a permanent magnet fixed to said suspension; and a solenoid provided so as to be opposed to said permanent magnet, for attracting said permanent magnet by passing a current in a first direction and repelling said permanent magnet by passing a current in a second direction opposite to said first direction.
Preferably, the disk drive further comprises control means for controlling said solenoid so that when said disk drive is powered off, a current is instantaneously passed through said solenoid in said first direction to attract said permanent magnet to said solenoid, whereas only when said disk cartridge is inserted into said disk drive and said disk drive is powered on, a current is instantaneously passed through said solenoid in said second direction to repel said permanent magnet from said solenoid.
The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention.